initial commit

git-svn-id: file:///home/ps/projects/distributor/trunk@1 4c72226d-0938-4c61-bee9-4ad40ed711b9
2011-01-20 22:15:41 +00:00 · 2011-01-20 22:15:41 +00:00 · 7db1f7a975
commit 7db1f7a975
4 changed files with 434 additions and 0 deletions
--- a/dist.c
+++ b/dist.c
@ -0,0 +1,155 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+
+#include "utils.h"
+
+extern char m_buffer[4096];
+
+#define BANNER "220 " HOSTNAME " SMTP"
+#define HELOANSWER "250 " HOSTNAME
+#define CMDUNKNOWN "502 command unimplemented"
+#define DOMAINUNKNOWN "553 unknown domain"
+#define TEMPERROR "421 delivery error, please retry later"
+#define DEFERROR "521 permanent delivery error, do not retry"
+#define PORT 25
+
+#define fail() do { perror(__FILE__ ":"); exit(-1); } while(0);
+struct serverinfo
+{
+  char *address;
+  unsigned port;
+};
+
+char *domains[]={"fakehermes.org","iteisa.net",NULL};
+struct serverinfo servers[]={
+  {"mail.gutierrezdequevedo.com",2525},
+  {"94.23.193.98",25}
+};
+
+unsigned long connid=0;
+
+struct serverinfo *get_server(char *domain)
+{
+  int i;
+  for(i=0;domains[i];i++)
+    if(!cmp(domain,domains[i]))
+      return &servers[i];
+
+  return NULL;
+}
+
+char *get_domain(char *line)
+{
+  char *strtmp=NULL;
+  char *buf=NULL;
+
+  safestrdup(buf,strchr(line,'@')+1);
+  safestrdup(strtmp,strtok(buf," \"><"));
+
+  condfree(buf);
+  return strtmp;
+}
+
+void handle_new_connection(unsigned long p_connid,int fd)
+{
+  char *buf=NULL;
+  char *from=NULL;
+  char *to=NULL;
+  char *domain=NULL;
+  char *serveraddress=NULL;
+  int fdin=-1;
+  int fds[2];
+  char databuffer[8192];
+  int bytesread;
+  int fdread,fdwrite;
+  struct serverinfo *server;
+
+  connid=p_connid;
+
+  write_string(fd,BANNER);
+
+  while(!socketeof(fd))
+  {
+    free_and_read_string(buf,fd);
+    if(!cmp(buf,"HELO")||!cmp(buf,"EHLO"))
+      write_string(fd,HELOANSWER);
+    else if(!cmp(buf,"MAIL FROM"))
+    {
+      safestrdup(from,buf);
+      write_string(fd,"250 Ok");
+    }
+    else if(!cmp(buf,"RCPT TO"))
+    {
+      safestrdup(to,buf);
+      domain=get_domain(to);
+      if(NULL==(server=get_server(domain)))
+      {
+        write_string(fd,DOMAINUNKNOWN);
+        exit(-1);
+      }
+      condfree(domain);
+      break;
+    }
+    else
+      write_string(fd,CMDUNKNOWN);
+  }
+  if(-1==(fdin=create_connected_socket(server->address,server->port)))
+  {
+    write_string(fd,TEMPERROR);
+    exit(-1);
+  }
+  do /* manage errors as we would do an exception, all in one point */
+  {
+    /* reproduce initial conversation on the new server */
+    free_and_read_string(buf,fdin); /* read banner */
+    write_string(fdin,"HELO " HOSTNAME); do { free_and_read_string(buf,fdin); } while('-'==buf[3]);
+    write_string(fdin,from); do { free_and_read_string(buf,fdin); } while('-'==buf[3]);
+    if(cmp(buf,"250")) { write_string(fd,DEFERROR); break; }
+    write_string(fdin,to);
+    /* now just copy data from one server to the other */
+    while(1)
+    {
+      fds[0]=fd; fds[1]=fdin;
+      can_read(fds,2,-1);
+      if(can_read(&fd,1,0)) { fdread=fd; fdwrite=fdin; }
+      else { fdread=fdin; fdwrite=fd; }
+      bytesread=read(fdread,databuffer,sizeof(databuffer));
+      if(bytesread<=0||write(fdwrite,databuffer,bytesread)<=0);
+      {
+        closeskt(fd);
+	closeskt(fdin);
+        break;
+      }
+    }
+  }
+  while(0);
+  condfree(buf); condfree(to); condfree(from); closeskt(fd); closeskt(fdin);
+  exit(0);
+}
+
+int main(int argc, char **argv)
+{
+  int fd_server=-1,fd=-1;
+  unsigned long conn=0;
+
+  /* ignore dying child */
+  signal(SIGCHLD,SIG_IGN);
+  openlog("dist",0,LOG_MAIL);
+  if(-1==(fd_server=create_listening_socket(PORT))) fail();
+  while(-1!=(fd=accept(fd_server,NULL,0)))
+  {
+    debug("New connection!");
+    ++conn;
+    switch(fork())
+    {
+      case 0: closeskt(fd_server); handle_new_connection(conn,fd);
+      case -1: fail();
+      default: closeskt(fd);
+    }
+  }
+  close(fd_server);
+  closelog();
+
+  exit(0);
+}